1. Field of the Invention
The invention relates in general to elevator systems, and more specifically to elevator systems which include means for providing audible messages in a plurality of elevator cars.
2. Description of the Prior Art
In the past, audible, informative messages have been produced in elevator cars, with the messages being prerecorded on tape, or other suitable recording means. Recently, several different techniques have been developed for synthesizing human speech electronically, and speech synthesizer processor units are now available and are being applied to many different applications. In the elevator application, the greatest need for audible in-car messages is in a bank of elevators, i.e., installations having a plurality of elevator cars controlled by a central supervisory processor. While large scale integrated circuits have lowered the cost of such speech synthesizer systems, the overall cost in providing such systems for a bank of elevator cars is still appreciable, because of the plurality of cars involved. Concurrently filed Application Ser. No. 215,893, entitled "Elevator System", filed in the names of K. M. Eichler, A. F. Mandel and D. A. Bauman, which application is assigned to the same assignee as the present application, discloses and claims a new and improved elevator system which substantially lowers the cost of the use of speech synthesis in an elevator system.
In this co-pending application, a single central processing unit (CPU), a single vocabulary source, and a single message instruction source, are required for serving a plurality of elevator cars. The only per-car apparatus required for the communication system is the speech synthesizer unit, external analog filtering and amplification, and the speaker. Notwithstanding the fact that the message center, vocabulary source, and CPU are common to all of the cars of the bank of cars, audible messages may be simultaneously provided in all of the cars by an "interleaving" arrangement which permits different, or like, audible, informative messages to be produced without interruption. The present invention is an improvement on speech synthesis systems for elevators, which improvement may be used by the system disclosed in the co-pending application.